Open Redirect in @Backstage Plugin-Auth-Backend
CVE-2026-32235
Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.
Vulnerability class: Open Redirect
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (12.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 12th percentile — 12.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- @Backstage Plugin-Auth-Backend — versions < 0.27.1
- Linuxfoundation Backstage
Weakness classification (CWE)
References
- github.com/backstage/backstage/security/advisories/GHSA-wqvh-63mv-9w92 (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-32235?
- CVE-2026-32235 is a medium-severity vulnerability in @Backstage Plugin-Auth-Backend, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 5.9/10. Published 2026-03-12.
- How severe is CVE-2026-32235?
- Medium severity. CVSS v3 base score is 5.9 out of 10.